The present invention relates to a portable self-contained solar powered water purifier, and more particularly, to such a water purifier which includes an electrolytic purification cell for purifying water into which the purifier is placed.
For sanitation and purification of swimming pools, spas, and other bodies of water, it is well known to use chlorine to destroy living bacteria and algae material in water. Treatment of water through the use of chlorine also results in chemical imbalance, requiring the addition of other chemicals to counteract the effect of chlorine. Further, the amount of chlorine that is required varies from time to time with the amount of usage and weather conditions. It is well recognized that chlorine must also be continually added, at prescribed intervals, to maintain the desired sanitary conditions, and as a result, chlorine is not an efficient nor a particularly economical algaecide agent. In addition, it is not generally accepted as healthful. Furthermore, there is an increasing public awareness of the dangers of handling, storage and use of chlorine for water sanitation purposes.
For a long period of time, it has also been generally known that metallic ions kill or control algae and bacteria. For example, silver is effective to kill or otherwise prevent propagation of most types of bacteria. Copper ions have also been well known as being effective in killing and preventing the growth of algae. Other metallic ions, such as zinc, aluminum, gold and many others, can be used in a similar way, with varying degrees of effectiveness.
Current devices and delivery systems have been historically uneconomical and bulky in utilizing metallic ions. Known devices and equipment have generally utilized high powered electrical equipment (120V or 220VAC power sources or DC electrical currents regulated and controlled from a 120VAC or 220VAC source). As will be appreciated, such equipment is expensive, complicated and generally requires special permanent installation and regular adjustments, thus resulting in high manufacturing and installation costs.
Other known conventional metallic ion devices or delivery systems use low voltages, for example, from 1-30 volts, either AC, DC or reversing DC. Some of the drawbacks with these systems have included excessive gassing, corrosion and accumulation of scales and deposits, which obviously result in reduced efficiency and/or the necessity of repetitive disassembly and cleaning of the devices/systems.
Examples of the high powered metallic ion delivery systems or equipment are shown in U.S. Pat. Nos. 4,328,084 and 4,525,272. An example of a low powered metallic ion delivery device/system is shown in U.S. Pat. No. 4,337,136.
In my aforementioned co-pending continuation and parent applications identified above, I have disclosed a general construction for a portable, self-contained solar powered water purifier. As disclosed, the water purifier includes a buoyant housing having solar cell means supported above water to be treated, purification means in the form of a sacrificial (copper/silver) anode and cathode (spiral wire spring) depending from the housing so as to be positioned in water to be treated, and means for electrically connecting the solar cell means to the purification means to operate the purification means when the purifier is placed in water to be treated. Reference is made to these patent applications for other disclosed features of my solar powered water purifier.
Further research has indicated that additional features should preferably be employed in order to provide a highly efficient and long lasting solar powered water purifier.
Where a hermetically sealed plastic housing is employed for buoyancy, it is difficult to maintain a seal between a substrate supporting the solar cells and the housing. Temperature increase causes the hermetically sealed plastic housing to be warmed up, and air trapped within the housing expands and causes the entire housing to be distorted to a shape which can disrupt or break the seal between the solar cell substrate and the housing. As a result, water can enter in the housing under the solar panel substrate causing corrosion and electrical shorting of exposed electrical contacts.
Another problem relates to the use of galvanized steel wire for the wire spring electrode in the purification cell. It has been discovered that rust and corrosion problems are severe when using galvanized steel wire, which are caused by chemical attack from the chlorine in the water, the water itself, and also a reverse current which generates at night. The difference between the copper/silver electrode and the zinc plating on the galvanized wire electrode causes a reverse current that is generated at night. While this creates a very efficient electrolytic cell, it results in the ionizing of the galvanized wire spring instead of the copper/silver electrode. This was found to occur only at night because the solar panel was not producing enough current to overcome this effect.
Still another problem in the original water purifier system included the use of a cage surrounding the anode and cathode electrodes. It was thought that this cage would eliminate the concern of consumers leery of a shock hazard and also would prevent a stick or other debris from getting stuck in the electrodes. It has been discovered; however, that the cage restricted water flow and did not function in the manner intended, and further resulted in a higher manufacturing cost.
Still a further problem relates to the location of the lanyard ring which enables the user to position the water purifier, as desired. With the prior hermetically sealed plastic housings, a hole had been drilled in the overlapping flanges forming the upper and lower halves of the housing, but it was discovered that in some of the units, the drilled hole allowed water to enter into the hermetically sealed housing, making it heavier and causing it to sink. This was not discovered until heat caused the housing to expand, thus causing water to be sucked in through the drilled hole for the lanyard ring.
While all of the above problems did not result in a totally unworkable unit, they nevertheless presented significant problems which needed to be addressed in order to provide a highly efficient and durable unit for the consumer. In some cases, the previous design shorted out due to water ingestion and became inoperative after an average of 30 days in service. The solutions for these and other problems, as well as new and improved constructions and features, will be discussed in detail below.